[quote name='Vincent_Core']Not to sound like an asshole or anything, but I don't see why anyone cares if she died. People die all the time. Are you going to feel sad for the random middle age woman that died just now in Canada or for the teenage kid in Germany that died seconds ago?[/QUOTE]
You're correct that at the end of the day none of us should shed a tear over this. Still, people can be sad they lost a performer they enjoyed. Personally, I only enjoyed her as Luanne on KOTH, and seeing as that series is over I'm not losing much. So are the reasons selfish? Yeah, kind of. Oh well right? Actors exist to give enjoyment to others. So to answer your question, people will care if they had any emotional investment (in this case they may have liked her acting, thought she was attractive, etc.) In your examples, you list people that no one has emotional investments to. That's the key difference.
I do see the angle you're coming from though - our society worships celebrities too much. Regardless, it's still appropriate to have a reaction to her death or even a modicum of sadness.